This application claims priority to United Kingdom Patent Application Number 0190177.6, filed Apr. 12, 2001.
This invention concerns improvements in or relating to foam articles. The invention has particular, but not exclusive, application to foam articles for use as masking materials when painting part of a vehicle to protect another part of the vehicle so that paint is only applied to the selected part of the vehicle. The invention also concerns a method of manufacturing such foam articles.
More specifically, the invention relates to foam articles for use as masking materials to block temporarily a gap between two parts of a vehicle to prevent paint entering the gap when the vehicle is being spray painted. The foam articles of this invention are especially suitable for use in vehicle body shops when re-spraying part of a vehicle following a repair.
It is already known to use masking materials in the form of an elongate foam strip to fill the gap between a movable part of the vehicle such as a door, hood or trunk and an adjacent part of the vehicle. Typically the foam strip has a longitudinally extending stripe of pressure sensitive adhesive by means of which the foam strip can be secured in the required position prior to painting and subsequently removed after painting.
The size and shape of the gap, and the available surface for mounting the foam strip may vary according to the position of the gap. For example, in a vehicle, the xe2x80x9cAxe2x80x9d post is the pillar situated between the vehicle body and the front edge of the front door, the xe2x80x9cBxe2x80x9d post is the pillar situated between the rear edge of the front door and the front edge of the rear door, and the xe2x80x9cCxe2x80x9d post is the pillar situated between the rear edge of the rear door and the vehicle body.
Typically, the xe2x80x9cAxe2x80x9d post supports the hinges for the front door, the xe2x80x9cBxe2x80x9d post supports the catch for the front door and the hinges for the rear door, and the xe2x80x9cCxe2x80x9d post supports the catch for the rear door. Often, a different type of foam strip is required to block the gap formed at each of these positions with each type of foam strip being provided in a range of sizes to accommodate variations in the dimensions of the gap between different makes or models of vehicle.
As a result vehicle body shops have to stock many types of foam strips in a variety of sizes to cover all possible applications. This is expensive both in terms of the amount of stock required and the space required to store the stock.
Furthermore, the user has to select and fit the correct type and size of foam strip for a given application, and use of the wrong foam strip may allow paint to penetrate the gap requiring corrective work to be carried out. This involves extra time and materials to complete a repair which reduces efficiency and profitability.
A foam strip is disclosed in International Patent Application No. WO99/52646 assigned to the assignee of the present application having a generally elongate cross-section with rounded ends which can be used as a masking material in more than one position when painting a vehicle. In particular, the foam strip of this application can be used to mask the gap formed at the xe2x80x9cAxe2x80x9d or xe2x80x9cBxe2x80x9d post of a vehicle as well as the gap formed between the rear edge of the vehicle body and a tailgate.
Such foam strip reduces the number of types of foam strip required for use at different positions of the vehicle and offers significant advantages and benefits to the user by allowing the same foam strip to be used in more than one location.
The problem still remains however that a given thickness of foam strip may not be capable of masking gaps of different size and different thicknesses of foam strips may still be required for effective masking of these gaps.
Moreover, the foam strips currently used as masking materials including the foam strip of WO99/52646 require access to the gap to be masked for securing the foam strip by means of the adhesive stripe and particular problems arise when masking the xe2x80x9cAxe2x80x9d post. Thus, there is only limited access to the gap in both the closed and open position of the door for inserting and sticking the foam strip to the appropriate surface. As a result, attaching the foam strip in the required position to mask across the gap when the door is closed is often a difficult and time consuming operation.
Furthermore, the existing foam strips including the foam strip of WO99/52646 are only suitable for use once and, after painting, are removed and thrown away. Thus, on first use, the exposed portion of the foam strip is painted and the foam strip cannot be re-attached to conceal the painted portion and present a new, clean portion of the strip. As a result, re-use of the foam strip is at best unsatisfactory and is generally avoided.
The present invention provides a foam article which can be used as a masking material having an even wider range of application for masking gaps of different types and different sizes than existing masking materials.
Furthermore, the present invention provides a foam article for use as a masking material that is capable of being secured in position without the use of adhesive.
Moreover, the present invention provides such a foam article for use as a masking material that can be used where access to a surface for adhesively securing the article is limited or restricted.
Additionally, the present invention provides such a foam article for use as a masking material that can be used more than once.
More specifically, the present invention provides a foam article, the manufacture of such article and the use thereof as a masking material to mask a gap when painting a vehicle which has generally universal application for masking gaps at different locations and in a range of sizes.
In one aspect, the present invention provides a foam article for use as a masking material comprising a plurality of elongate foam strips, each strip having a longitudinally extending edge and being joined at said longitudinally extending edge to a longitudinally extending edge of at least one further elongate strip by a seam common to all said strips.
By forming the foam article from a plurality of foam strips, the foam article can be adapted to provide masking material of the required thickness for use in any selected one of a range of different types and size of gap by the selection of the appropriate number of foam strips to mask the gap.
Moreover, it may be possible to locate and retain the masking material without the use of adhesive by relying on the compression of the masking material through the selection of the appropriate number of foam strips to wedge the masking material in the gap.
Furthermore, after use, the masking material can be re-used by arranging the foam strips to mask a gap with fresh or clean surfaces of the masking material exposed.
Typically, each foam strip is of generally elongate cross-section having longitudinally extending edges on opposite sides of a longitudinally extending body portion.
In one embodiment, the common seam joins all the foam strips along one side edge and the other side edge is free. In this way, the foam strips are secured longitudinally to radiate from said common seam. As a result, the foam strips can be arranged to superimpose different combinations of the foam strips to provide different thicknesses of masking material.
Advantageously, the foam strips are separable along said common seam. In this way, any foam strips that are not required can be removed to leave the desired thickness of masking material.
Furthermore, after use, any foam strips that are painted can be removed and the remaining foam strips arranged to provide masking material for another use.
Removing any painted foam strips reduces the thickness of masking material that can be produced with the remaining foam strips. It may be possible to re-use the masking material without reducing the thickness by re-arranging the foam strips so that any painted foam strips are concealed by unpainted foam strips when the masking material is secured in position.
In another embodiment, the common seam joins all the foam strips along one side edge and a further common seam joins all the foam strips along the other side edge. In this way, the foam strips are secured relative to each other in a superimposed relationship to provide masking material having a thickness corresponding substantially to the combined thickness of the individual foam strips.
Advantageously, the foam strips are separable along said common seams. In this way, the outermost foam strips can be removed to vary the thickness of the masking material.
Additionally, after use, any foam strips that are covered in paint can be removed and the remaining foam strips arranged to provide masking material for another use.
In either construction, the number and/or thickness of the foam strips may be chosen to provide the masking material with any desired range of thicknesses by selecting an appropriate combination of foam strips.
For example, the foam strips may all be of the same thickness or at least one foam strip may be of different thickness to the other foam strip(s). Generally, the foam strips are selected when combined to provide masking material having a maximum thickness of up to about 30 mm.
Furthermore, the foam material of the foam strips may be chosen to provide the masking material with any desired properties. For example, the foam strips may all be of the same type of foam material or at least one foam strip may be of a different type of foam material.
Typically, the foam material employed may be an open or closed cell polymeric foam that is resiliently compressible for conforming to a required shape for a given application. Foams having a density in the range of from 20 to 30 Kg/m3 are generally found to be useful for use as masking materials.
The foam strips may all be of the same colour. Alternatively, different properties or characteristics of the foam strips such as thickness or type of foam material, may be distinguished by different colours or combinations of colours. Colour coding the foam strips in this way has advantages for both the manufacture and use of masking materials with the appropriate combination of foam strips for the required application.
Different colours may also be used to provide a colour contrast de-limiting a sight line at the boundary between differently coloured portions of the foam strips to assist in accurately positioning the masking material.
Typically, the foam strips are made of cold weldable material. In this way, the foam article may be produced by forming a cold weld seam along at least one side edge of the foam strips. Preferred foam materials include polystyrene, polyvinylchloride, polyethylene, polyurethane, polyisocyanate, polyphenol, polyester and silicone foams.
The foam material may be cold welded by applying pressure to superimposed layers of foam web with a former such as a rotatable pressure roller or wheel so as to compress the layers of foam web sufficiently to cause the foam layers to fuse together.
A cold weld seam formed in this way unites the layers of foam material to each other along the seam and allows individual layers to be separated from the other layers which remain united along the seam.
The foam articles may be provided with a longitudinal adhesive stripe on at least one foam strip for sticking the foam article in position. Preferred adhesives are pressure sensitive adhesives such as a hot melt rubber adhesive. The adhesive may be applied to the foam by any suitable means, for example die coating, before or after the cold welding operation.
In another aspect, the present invention provides a method of manufacturing a foam article for use as a masking material including the steps of providing a plurality of sheets of foam material, superimposing the sheets of foam material, joining the sheets of foam material at a plurality of spaced positions by longitudinally extending parallel seams, and separating the sheets of foam material along the seams to produce a plurality of elongate foam articles, wherein each foam article comprises a plurality of foam strips joined together by at least one seam a side edge of the foam strips.
The foam article produced by the above method may have the foam strips joined together along both side edges so that the foam strips are secured in superimposed relationship to each other. This form of the foam article can be used as a masking material and can be adapted to a required thickness of masking material for a given application by removing one or more of the foam strips.
Alternatively, the foam strips may be joined together along one side edge only so that the foam strips radiate from the seam. This form of the foam article can also be used as a masking material and can be adapted to any desired thickness by superimposing the appropriate number of foam strips.
Typically, the foam material is cold weldable and the seams are formed by compressing the sheets of foam material to fuse the sheets together along the seams. The cold welding operation may be effected by a former such as a rotary pressure wheel or roller and a plurality of seams may be formed simultaneously by arranging a series of formers transversely spaced across the superimposed sheets of foam material.
In one method, the foam strips are joined together by cold weld seams along both side edges when the sheets of foam material are separated to produce one form of foam article, and the seam along one side edge can be optionally ruptured if it is desired to produce another form of foam article. In this way, both forms of the foam article each comprising a plurality of foam strips can be produced by the same method.
By forming the foam article with cold weld seams along one or both side edges of the foam strips, the foam strips can be arranged to provide any required thickness of masking material for a given application as described previously and, after use, the arrangement of the foam strips can be adapted so that the masking material can be re-used.
For example, where the foam strips are joined along both side edges, any painted foam strips may be removed to expose a new, unpainted foam strip below for re-use of the masking material.
Similarly, where the foam strips are joined along one side edge, any painted foam strips may be removed leaving the remaining new, unpainted foam strips for re-use of the masking material.
Alternatively, where the foam strips are joined along one side edge, the foam strips may be folded and superimposed in a different orientation so that the painted foam strips are concealed for re-use of the masking material.
The options and variations for altering and adapting the masking material for re-use are numerous and will be understood by those skilled in the art.
Thus, in another aspect, the present invention provides a foam article for use as a masking material comprising a plurality of foam strips, each foam strip having a body portion and side edges, and a cold weld seam releasably securing the foam strips together along at least one side edge whereby, in use of the foam article as a masking material, the arrangement of the foam strips can be adapted to enable the foam article to be re-used.
By releasably securing the foam strips, any foam strip that has been painted when the foam article is used as a masking material can be removed so as to leave new, unpainted foam strips for further use of the foam article as a masking material.
The foam articles of the present invention are particularly suited for use in masking a gap between two parts of a vehicle such as a door and the vehicle body or two doors. Thus, the foam article can be adapted to a range of gap sizes by selecting the combination of the individual foam strips to vary the thickness of the foam article.
Thus, in another aspect, the present invention provides a foam article for use as a masking material comprising a plurality of foam strips, each foam strip having a body portion and side edges, and a cold weld seam releasably securing the foam strips together along at least one side edge whereby, in use of the foam article as a masking material, the arrangement of the foam strips can be adapted to vary the thickness of the foam article.
In yet another aspect, the present invention provides a method of masking a gap between two parts of a vehicle when painting at least one of the parts, the method comprising the steps of providing an elongate foam article comprising a plurality of elongate foam strips joined together by a seam along at least one side edge, and positioning the foam article to mask the gap.
The method may include the step of selecting a combination of foam strips to adapt the thickness of foam article to the gap to be masked.
The method may also include the step of wedging the selected combination of foam strips in the gap without the use of adhesive.
Wedging the selected combination of foam strips in position may be of particular benefit if access to the gap is limited or restricted, for example when masking an xe2x80x9cAxe2x80x9d post. Thus, the selected combination of foam strips may be positioned in the gap and pulled through to wedge in the gap without the use of adhesive to secure the foam strip inside the gap.
In yet a further aspect, the present invention provides a foam article for use as a masking material comprising a plurality of superimposed foam strips releasably secured together.
The foam strips may be secured together by cold welding or adhesive or any other suitable method that allows selective removal of one or more foam strips. In this way, different thicknesses of masking material can be obtained and/or, after use, contaminated foam strips can be removed to expose fresh strips allowing the masking material to be re-used.
Other features, benefits and advantages of the invention in each of its aspects will be more readily understood from the description hereinafter of exemplary embodiments in which like reference numerals are used throughout to indicate corresponding parts.
The invention will now be described in more detail by way of example only with reference to the accompanying drawings in which like reference numerals are used to indicate corresponding parts.